A variety of systems and applications use stacks of sheets or plates or both, which may be made of metal, paper, plastic, or the like. Printing plates (hereinafter singly or collectively referred to as “plates”) are typically stacked in plate pallets which house the plates and facilitates their protection, transportation, and handling.
A system for handling printing plates will generally use cassettes having specific dimensions. Cassettes can usually be set to contain plates of various sizes, but all plates in the same cassette are of one size. The plates may be manually removed from the plate stack and inserted into the cassettes for use by the plate imaging system. Plates in a plate stack are separated by intermediate paper sheets, hereinafter referred to as separation paper.
Cassettes containing printing plates are heavy and bulky, and moving such cassettes requires complicated and expensive mechanisms and is time consuming; specifically, during the loading of the plates from the plate stacks into the cassettes. There is a widely recognized need for an automatic and efficient handling system for feeding plates directly from the original plate pallet into the imaging device, while obtaining and maintaining a precise position of the plates during the plate feeding process. This need is addressed by the invention described in commonly-assigned U.S. Publication No. 2009/0224464.
The plate stack received from plate manufacturers often comprises a stack of a few hundred plates. Each plate is separated from the next by separation paper, and the entire stack of plates is placed on a pallet. The stack of plates positioned on a pallet, are inserted as such into the plate loading system. The stack of plates must be inserted into the plate loading system precisely, in such a way that the plate pick up mechanism is perfectly aligned with a certain side of the plate stack and they are centered to.
The invention disclosed hereunder suggests a solution to the described problem.